In the 1980s peanut growers had Kylar to define rows and significantly improve harvest efficiency. Since its removal from the market a number of growth regulators have come and gone, often leaving growers with little defense against harvest time yield losses.

As growers in the upper Southeast get ready to dig peanuts, the expected rainfall from Hurricane Hanna and subsequent storms brewing in the Atlantic Ocean could spell major problems for peanut harvests.

In 2007, drought plagued most of the peanut growing system, reducing the pod load on crops from north Florida to Virginia. Fortunately, ideal weather conditions at harvest time allowed most growers to pick a high percentage of their crop.

If 2008 harvest weather is dominated by tropical weather fronts, growers have few options to insure efficient harvest.

In recent years many growers have planted and dug peanuts using GPS-guided equipment. To be accurate enough to dig peanuts usually requires RTK capabilities which narrow the accuracy window to less than an inch.

For growers without GPS-guided equipment, harvest time yield losses remain a problem. Arguably the largest losses in yield in a peanut crop come from digging the crop.

With peanut acreage trying to make a come back in the upper Southeast, researchers at North Carolina State University established a test to monitor the efficacy of a new growth regulant — Apogee — for use on peanuts.

Speaking at the recent Northeast Ag Expo, Perquimans County Extension Coordinator Lewis Smith says research at C.A. Perry Farms in Tyner, N.C., indicates Apogee under some growth conditions can help farmers avoid harvest losses and improve overall yield of peanuts.

Smith notes that the tests at the Perry Farm in northeast North Carolina were plagued by drought throughout some of the growing season. Costs under these type conditions may not merit use of Apogee, though in addition to row definition, the product has shown some yield enhancement capabilities in other test across the state, Smith adds.

Apogee (prohexadione calcium) was first labeled for use on apples. It saved apple growers in the Pacific Northwest considerable time and money by reducing pruning time and helping protect orchards from yield-robbing fire blight.

In peanuts the product increases peg strength and reduces canopy growth. In years with adequate to high rain, peanut fields can look like a flat, green wall horizontal to the ground. By shaping the crowns of the peanut rows, a growth regulant creates a ripple, or dip in the middle of the rows, providing a guiding line for growers to dig.

Apogee should be applied when 50 percent of the vines from adjacent rows are touching. In years with above average rainfall, usually created by late summer tropical storm and hurricanes, two sequential applications of 7.2 ounces per acre, spaced 2-3 weeks apart are usually required.

North Carolina State University Peanut Specialist David Jordan conducted a series of tests to determine the effects of peanut cultivar and digging date on row visibility and pod yield when prohexadione calcium was applied sequentially at 7.2 ounces per acre at 50 percent row closure followed by a second application 2 to 3 weeks later.

Although differences in row visibility were noted among cultivars, prohexadione calcium improved row visibility in almost every experiment regardless of cultivar. The Virginia market type cultivars NC 12C and Perry were more responsive to broadcast applications of prohexadione calcium in terms of pod yield than the Virginia market type cultivars NC-V 11 or VA 98R, according to Jordan.

Response of these cultivars was independent of digging date. In other experiments, prohexadione calcium improved row visibility of the cultivars AT VC-2, Gregory, NC-V 11, Perry, VA 98R, and Wilson but did not increase yield when compared with non-treated peanuts.

In a final experiment, prohexadione calcium improved row visibility of the Virginia market type cultivars Brantley, CHAMPS, Gregory, and Phillips and the experimental lines, N02006 and VT 976133 at 3 of 4 sites. Row visibility for the experimental line N01013T was improved at 2 of 4 sites by prohexadione calcium. Prohexadione calcium increased row visibility of Georgia Green (runner market type), Tamspan 90 (Spanish market type), and Gregory (Virginia market type) but did not affect pod yield of these cultivars, Jordan concludes.

e-mail: rroberson@farmpress.com